Your own garage is not just a place to park a car, but a full-fledged workshop and warehouse that requires reliable protection from bad weather and intruders. Self-construction of a metal frame allows you to significantly save your budget, since the cost of ready-made modular structures is often inflated by intermediaries. Smartly designed frame ensures the durability of the entire structure, regardless of what you plan to cover it with in the future.
The construction process begins long before the purchase of the first meter of rolled metal, at the stage of design and selection of materials. Errors made when calculating loads or choosing the cross-section of beams can lead to roof collapse under the weight of snow or deformation of walls. In this article we will analyze all the stages of creating a strong and durable structure, based on proven building codes.
To work, you will need not only physical strength, but also specific tools, including a welding machine and an angle grinder. The quality of welds and the accuracy of assembling components directly affect geometric stability the entire building. It is important to understand that you cannot skimp on the quality of metal or anti-corrosion treatment, since repairing an assembled frame is an extremely labor-intensive and expensive task.
Selection of materials and design of structure
The basis of any metal garage is a supporting skeleton, which is most often assembled from a profile pipe. For vertical posts and roof trusses, the optimal choice is a square pipe with a cross-section of 100x100 mm or 80x80 mm with a wall thickness of at least 4 mm. Horizontal jumpers and stiffeners can be made from a profile of a smaller cross-section, for example, 60x40 mm or 40x40 mm, which allows reducing the overall weight of the structure without loss of strength.
When designing, it is necessary to take into account wind and snow loads typical for your region. If you live in an area with heavy snowfall, the pitch of the roof trusses should be reduced and the slope angle made steeper so that precipitation does not linger on the surface. Load capacity calculated with a margin, since the weight of the metal itself will be added to the weight of the sheathing, insulation and possible equipment inside.
⚠️ Attention: Using round pipes for racks is possible, but it significantly complicates welding work and joining of units, requiring special conductors or precise trimming of the ends.
To connect elements, electric welding is most often used, which ensures the solidity of the structure. However, in some cases, especially when assembling demountable garages, a bolted connection is used. Profile pipe rectangular cross-section is more convenient to install, since it is easier to attach sheets of corrugated sheets or sandwich panels to flat edges.
Calculation of the amount of metal
For a standard 6x4 meter garage, approximately 1.5–2 tons of rolled metal will be required, including a reserve for scraps and technological losses during cutting.
Preparing the foundation and bottom trim
A metal frame requires a reliable foundation that will prevent subsidence and distortion of the racks. The most common solution is a strip foundation poured around the perimeter of the future building, or a monolithic slab. The laying depth depends on the level of soil freezing, but for light metal structures, a buried tape of 50-70 cm with mandatory reinforcement is often sufficient.
The critical step is installation anchor bolts or embedded parts in concrete. It is to them that the lower frame trim will be welded or screwed. The distance between the fastening elements must strictly correspond to the pitch of the vertical posts, otherwise during installation there will be difficulties with leveling the structure.
- 🏗️ Dig a trench under the strip foundation and install the formwork, not forgetting about waterproofing the walls.
- 🔩 Lay the reinforcement frame and install anchor studs with precise reference to the axes of the walls.
- 🧱 Pour concrete brand M200-M250 and wait until it reaches full strength (at least 20-25 days).
The lower piping is made of a powerful channel (for example, 14P or 16P) or a large-section profile pipe. Before installation on concrete, a layer of waterproofing must be laid, usually roofing felt or bitumen mastic, to cut off capillary moisture. The metal of the lower trim must be carefully treated with an anti-corrosion compound, since this part of the structure is most susceptible to moisture from the ground.
☑️ Checking the foundation before installation
Assembling vertical posts and walls
Wall installation begins with the installation of corner posts, which are aligned strictly according to a plumb line or laser level. Any deviation from the vertical at this stage will lead to distortion of the entire structure and problems when installing the gate and roof. After fixing the corner elements, the control cord is pulled, along which the intermediate posts are set at the selected pitch, usually 2.5–3 meters.
To ensure spatial rigidity, horizontal connections are installed immediately after installing the pillars. They can be located at the top level of the gate, along the bottom of window openings and under the roof. Braces (diagonal elements) in the plane of the walls significantly increase the resistance of the frame to lateral wind loads, turning a set of pillars into a single rigid frame.
Welding of assemblies should be carried out in compliance with the technology: first, tacks are made to fix the position, the geometry is checked, and only then a continuous seam is applied. It is important to avoid overheating the metal at one point so as not to weaken the steel structure. After cooling, all welds are cleaned of slag and coated with a primer to protect them from rust.
| Frame element | Recommended cross-section | Installation step | Connection type |
|---|---|---|---|
| Corner posts | 100x100x4 mm | In the corners | Butt welding |
| Intermediate posts | 80x80x3 mm | 2.5 - 3.0 m | Butt welding |
| Horizontal connections | 60x40x2 mm | By height | Overlap welding |
| Diagonal braces | 40x40x2 mm | In the spans | Butt welding |
Manufacturing and installation of rafter system
The garage roof is most often made of a single-pitch or gable roof. For the single-pitch version, the trusses are triangular structures, the angle of inclination of which depends on the selected roofing material. For corrugated sheeting, the minimum angle is 8-10 degrees, for metal tiles - at least 14 degrees, to ensure effective drainage of water and snow.
It is more convenient to assemble the trusses on the ground, welding them in a horizontal position according to a template. This guarantees the identity of all elements and high quality welded joints. Finished trusses are lifted up using a winch or crane and welded to the vertical posts. The distance between the trusses is usually 3 meters, but when using lightweight roofing materials, the pitch can be increased.
An important element is ridge run (for a gable roof) or top trim (for a single-pitch roof), which connect all the trusses into a single system. To strengthen the structure, longitudinal stiffening links are installed between the trusses. In places where trusses rest on racks, sheet metal gussets 8-10 mm thick are often used to distribute the load.
⚠️ Attention: When welding trusses on the ground, take into account their weight - it will be impossible to lift the assembled structure manually; provide safety precautions and lifting mechanisms in advance.
If you are planning an insulated garage, then at the installation stage of the rafter system it is necessary to provide places for attaching the vapor barrier and the internal contour of the sheathing. Metal frame is an excellent conductor of cold, so the presence of an air gap between the metal and the insulation is critical to prevent the formation of condensation.
To protect welds from corrosion, use a rust converter before painting, and apply the paint itself in two layers with intermediate drying.
Installation of gates and doorways
Openings for gates and gates are formed at the stage of assembling the wall frame. For this purpose, more powerful profile pipes are used, which act as racks and lintels of the opening. The design of the gate posts must be reinforced with additional vertical stiffeners, since they bear the main dynamic load when opening and closing.
If you are planning to install automatic sectional or overhead gates, the requirements for the rigidity of the opening increase many times over. Metal guides are attached directly to the frame, and any deformation of the racks will lead to jamming of the mechanism. In such cases, it is recommended to double piping the opening or use pipes with increased wall thickness.
- 🚪 The width of the gate opening should be 20-30 cm larger than the width of the car for a comfortable check-in.
- 🔧 The gaps between the gate leaves and the frame must be at least 5 mm on each side.
- 🛡️ For swing gates, the hinges are welded taking into account possible shrinkage of the foundation (the gap at the bottom is up to 10 cm).
The gate, as a rule, cuts into one of the gate leaves or is mounted as a separate element in the wall. In any case, the top lintel above the gate must be strong enough to withstand the weight of the door and wind pressure. Loops for metal gates they are selected based on the weight of the leaf with a margin of 30-40%.
Anti-corrosion protection and finishing
Without protection, metal quickly rusts, losing its load-bearing capacity and aesthetic appearance. The first stage of protection is mechanical cleaning of all surfaces from rust, scale and welding deposits. To do this, use a sander with flap wheels or sandblasting, which ideally cleans hard-to-reach areas.
After cleaning, the surface is degreased and coated with a metal primer containing corrosion inhibitors. Particular attention is paid to welds and cutting areas where the protection is most compromised. For durability, it is recommended to use epoxy-based primers, which create a strong chemical bond with the metal.
Recommended processing scheme:1. Cleaning to white metal (Sa 2.5)
2. Degreasing with white spirit
3. GF-021 primer or epoxy primer (2 layers)
4. Finish enamel (2 layers)
The final coating is selected depending on operating conditions and budget. Alkyd enamels are affordable, but require updating every 3-5 years. Polyurethane and acrylic coatings are more expensive, but last for decades, maintaining color and gloss. The thickness of the dry layer of protective coating should be at least 80-100 microns for aggressive environments.
The quality of anti-corrosion treatment determines the service life of the garage to a greater extent than the thickness of the metal frame.
Is it necessary to insulate a metal garage?
Insulation is necessary if you plan to spend a lot of time in the garage in winter or store tools there that are sensitive to temperature changes. However, it is important to properly organize ventilation, otherwise the metal will “cry” due to condensation, which will lead to rapid corrosion of the car and the frame itself.
Which foundation is better for heaving soils?
On heaving soils that expand greatly when freezing, it is preferable to use a pile-screw foundation or a buried monolithic slab. The strip foundation can be pushed out by frost heaving forces, which will lead to distortion of the frame and destruction of welded joints.
Is it possible to assemble the frame without welding?
Yes, it is possible to use bolted connections using shaped elements (angles, plates). This allows you to assemble the garage like a construction kit, which is convenient for transportation, but requires more accurate initial markings and regular checking of the tightness of the bolts, as they can become loose due to vibration.